Refrigerator plant



Feb. v9, 1932. E. G, ROWLEDGE l 1,844,822

REFRIGERATOR PLANT Filed July 8, 1929 l), 2 Sheets-Sheet l -fyj Feb. 9, 1932.- E, G. ROWLEDGE 1,844,822

AREFRIGERATOR PLANT Filed July 8, 1929 2 She'etS-She. 2

Patented Feb. 9, 1932 UNITED STATES PATENT OFFICE Y ERIC GEORGE ROWLEDGE, OF NEW ELTHAM, LONDON, ENGLAND, ASSIGNOR T0 J".

STONE & COMPANY LIMITED, OF DEPTFORD, ENGLAND, .A COMPANY OF ENGLAND REFRIGERATOR PLANT Application led July 8, 1929, Serial N'o. 376,651, and in Great Britain J'uly 13, 1928.

This invention comprises improvements in refrigerator plant, particularly for use on vehicles such as railway carriages and vans. In such installations, the cold has been produced dynamically by evaporating a volatile liquid at a low temperature and pressure and re-condensing it at a higher pressure and temperature, the pressure being increased by a compressor driven from a running axle.

One object of this invention is to increase the cold storing capacity of the custon'iary brine or hold over tanks which are cooled by the evaporation of the volatile fluid and serve for absorbing heat leaking into the cold chamber during periods of idleness of the compressor. The capacity of brine for storing cold merely by changing its sensible heat is relatively7 small and it is not permis sible'to employ large brine tanks on vehicles, for example, as it is important to preserve as large a carrying capacity as possible. Thus, heretofore, the difficulty has been experienced that the plant, under certain climatic conditions, may produce too low a temperatur'e when running continuously and must be shut off for part of the time, whereas duringa prolonged period of standing there is insuliicient cold stored or accumulated for preserving the appropriate reduced tem perature in the cold chamber or van.

A further object of the present invention is to provide an installationof a compact character occupying a minimum of space and nevertheless possessing a relatively large capacity for storlng or accumulating cold, the cold accumulator being available for preserving the desired reduced temperature in the vehicle, compartment or chamber during idle periods of the compressor as when a vehicle stands in a siding or at a wharf or dock, to enable theplant to be run for the whole of the journey of the train and so obtain the maximum of refrigeration possible and at the Sametime to' permit the temperature inside the vehicle, compartment or chamber to be controlled within the desired limits.

With these objects in view refrigerator i vplant according to the invention comprises a thermodynamic source of cold associated with a cold accumulator utilizing the latent heat of a cold storing medium and consisting of one or more relatively small brine tanks or drums disposed ina well or chamber under the roof or on the walls of a vehicle, van or the like. Said chamber or the like has an automatically regulated communication with the insulated space or cold chamber in which reduced temperature is to be preserved. The cold storing agent with which such tank or tanks are charged is a chemical solution or brine, the nature, density, and freezing point of which is adjusted lso as to enable con gelation to take place at a predetermined temperature. The compressor and its associated refrigerating plant will be of such capacity that the compressor is capable, in addition to cooling the cold chamber, of eventually producing solidication or congelation of the brine whereby a large capacit y for storing cold is obtained owing to the latent heat of solidification of the ice crystals in the congealed brine. Thus, on a railway vehicle for example, the compressor may run the whole of the time that the train is running and at a speed proportional to theI speed of the axle from which it .is driven, and' after reducing the temperature of the cold chamber to the desired degree, the excess of refrigeration produced over and above that required for lthe maintenance of the desired temperature, is employed for con elation of the brine, or changing its state groin a liquid to a solid. In this way, an accumulation of cold is obtained, which is large re1- vatively to the dimensions ofthe apparatus employed and is available for maintenance of the, desired reduced temperature in the cabinet or chamber `during periods when thc vehicle and refrigerator plant are not running.

Various embodiments of the invention are illustrated by way of example in the accompanying drawings in which Figure lfis a cross section of a refrigerator cabinet suitable foruse on a railway vehicle.

Figures'2 and 3 are a longitudinal section `and across section respectively of a railway refrigerator van and v .Figure 4 shows an arrangementwsimilar to Figari 1 but provided with a number of cold l chambers to be kept at different temperatures.

In the arrangement illustrated in Figure 1, a brine tank 1, which may be a rectangular vessel having a semi-circular or spherical bottom, is arranged in a. well or top space 2 of a cold cabinet or chamber 3. The brine tank 1' is provided with the usual evaporator coil 1 for its positive cooling connected by the pipes 1 with the refrigerator compressor, not shown. The tank 1 itself is uninsulated, but is enclosed by insulating walls 4 which are spaced from it and one of which does not extend to the top of the cabinet, thus forming a duct 5 whereby the relatively warm air from the cabinet 3 may rise and pass over the Vtop of such wall and have access to the brine tank. A lower portion of one of these Walls has an opening 6 which may be closed by a flap, louvre, or valve 7 which is operatively connected by a linkage 8 with a thermostatic device 9 calibrated to operate the flap or valve 7 at the reduced temperature predetermined for the cabinet or chamber. The walls enclosing the brine tank may be lined with zinc and a receptacle may be provided therein for collecting and running off liquidcondensed upon the tank-and falling therefrom. The cabinet or chamber may be divided into. compartments by suitable partitions 10, and on thefiooring of each compartment there may be trays, flanges, or appropriate devices for causing foodstuffs and other articles to be placed clear of the walls in order to leave a circulation space for the air.

In operation, the fiap or valve 7v may be fully open when the train starts on a run and theI compressor commences work. LAt first, the refrigerating effect produced by the compressor will be utilized in coolingr the interior of the cabinet or chamber 3 together with the produce contained therein and overcoming the heat leakage into the same, dueto the thermal head across the insulation, which thermal head varies, of course, throughout the day and from day to day throughout the year. When the temperature within the cabinet is reduced to the predetermined degree, thethermostat 9 operates to close, 4wholly or partly, the Hap -or valve 7, such closure restricts or revents circulation through the tank chamer 2.of air rising from the compartments of the cabinet 3, -and avoids an unnecessarily low temperature in said cabinet, and so, as the heat loss through the insulation is directly proportional to the thermal head across the insulation, conserves the refrigeration be-- ing produced. Thus the refrigerating effect thereafter is utilized wholly or partly for taking out the vlatent heat of the brine solution and eventually, if the run is sufficiently rolonged, to congeal the brine to a solid'mass. en the valve or flap is fully closed by the thermostat, there is no outlet from the bottoni part. of the tank chamber 2.V Consequently, the only cooling eii'ect upon theair in lthe compartments ofthe cabinet 3 will be that which is due to cold air which may be spilled from the tank chamber due to vibration or movement of the vehicle. Naturally, when the temperature within the cabinet 3 rises above the predetermined degree, the thermostat 9 opens the flap or valve 7, or permits it to open, sothat air highly cooled by contact with the brine tank 1 is permitted to descend into the compartments thus givingy an automatic control of the cabinet temperature, as Will be readily understood.

In the arrangement shown in Figures 2 and 3, a number of drums 11 of circular section are suspended from the roof 12 of a cold storage or refrigerator Wagon. These drums 11 contain a chemical solution as described inthe foregoing paragraph through which pass ribbed evaporator pipes 11, connected in series. The cooling drums 11 are enclosed in a ,duct 13 insulated to prevent condensation of atmospheric moisture on the under side of such duct. The duct is carried down to floor level at one end 14 and is left open at the top at the other end 15. A lip 16 is provided to prevent excessive spilling of the cold air when the circulation has been stopped. The lower end of the duct 14 which is carried down to floor level is arrangedto be fitted with one or more frames containing louvres or shutters 17, `which are controlled by a thermostat 18 through the medium of a mechanical, electrical or hydraulic relay gear. As illustrated the thermostat 18 and louvres 17 are connected hydraulically by pi es 18. The thermostat is of the expanding ellows type and controls a ram adapted to displace oil in the pipes 18. At the end remote from the thermostat each pipe 18 communicates with a cylinder 18, containing a plunger suitably connected with the louvres 17. Im-

vpelled by displacement'of the oil brought about by the movements of the thermostat, the plunger in the cylinder`18 will follow said movements of the thermostat and thus adjust the air flow to suit the temperature conditions as explained in connection with Figure 1.

The air circulation is indicated by arrows. When the lower limit of the desired temperature in the van has been reached, the thermostat 18 operatesto close the shutters 17,4which prevents any more cold air being circulated through the van and itsstowage until such time as the temperature rises to the top limit when the thermostat operates to again open the shutters and permit circulation of the air. In the van actuallyillustrated it will be seen that the brine drum arrangement is duplicated and the two sets of drums 11 extend from either\side of a'centrally disposed thermostat 18 towards the ends of the van.

A further application of. the inventionkis shown in Figure 4. In this case it is desired to maintain three distinct temperatures in the three compartments 20, 21, 22 of a cabinet, having but one cooler unit 1 which, as will be seen from the sketch, is suspended in a well extended downwardly to form a central freez- 5 ing compartment 20, cooling this compartment/to a low temperature, say F. A second chill compartment 21 on the left is partitioned off by two insulated walls which form a cold air duct 23 as shown; the-right w hand side or cool cupboard 22 is arranged in a similar manner. Thermostatically controlled valves 7 are placed at openings 6 arranged at the bottom of each duct 23 and' in the manner already described control the 15 temperature in each compartment by regu- Ilating the circulation of the air from the cooler unit. Thus the chill" compartment might bekept at -40o F. and the cool, compartment at liti- F. The air circulation through the compartments and back by way of warm air ducts 24 is indicated by arrows. As .in the case of Figure 1, ice drawers 25 may, if desired be provided 1n they brine tanks 1.

Iclaim 1. Refrigerator installation for wheeled y vehicles, comprising an axle-.driven compressor operative for circulating a suitable medium in a closed circuit, said compressor be- 30 ing intermittently operated for undetermined periods incident to stopping and starting of the wheeled vehicle, an evaporator coil in said circuit adapted for producing cold, an elevated cold accumulator in heat exchange 3:. relation with said coil, said accumulator being adapted for utilizing the effects of the latent heat of a coldstorin medium, compartment walls enclosing a c amber containing said accumulator, said chamber'having free communication at its 'upper part with a refrigerated space in saidK vehicle, and a thermostatic control operative for regulating communication between the lower art of said chamber and said space substantially as 46 set forth. J v

2.. I'n a refrigerating installation for railroad cars subject to various stopping and starting operations for undetermined periods of timea thermo-dynamic refrigeratin apno paratus o erative during the periods o operation o the car, said apparatus having a low temperature element an elevated chamber, a brine accumulator located in said chamber and in h eat exchange relationship with said low temperature element, a refrigerating chamber having an air circulation connection with the elevated chamber, and valve means to control said circulation connection to induce freezing of the brine in the accumulator for use during said ndetermined periods of cessation of operatbn of the thermodynamic action. I

ERIC GEORGE( 'izowLEDGE.. 

